DEC A POD A . Til A LASSINA DM. 



MACROURA. 



GENUS CALOCARIS. Mmi. 



Generic Character. — External antennoi placed nearly on the 

 same line with the internal ; the peduncle cylindrical ; the penul- 

 timate joint the longest ; a large triangular scale reaching to the 

 end of the first joint. Internal antennce with two setse, more 

 than half as long as the external ; the peduncle cylindrical, with the 

 joints of nearly equal length. External pedipaljjs pediform, elon- 

 gate, with a long seta. First pair of feet somewhat unequal, 

 very long, compressed ; the arm slender, twice as long as the 

 wrist, which is very short, subtriangular, flattened, with the hand 

 somewhat gibbous, as broad as it is long ; the fingers more than 

 three times the length of the hand, slender, much flattened ; se- 

 cond pair of feet didactyle, resembling the former, but much 

 smaller ; third, fourth, and fifth pairs simple, long, and slender. 

 Carapace very large, terminating in an acute triangular rostrum, 

 from which is continued, backwards and outwards, on each side, 

 a raised line furnished with small acute spines. Eyes rudimentary, 

 subglol)Ose, without any pigment or cornea'. Abdomen long, com- 

 pressed, enlarged at the middle segment, contracted at each ex- 

 tremity ; the terminal joint, or central lamina of the tail, longer 

 than broad, rounded. 



Of this interesting fossorial form one species only is 

 known, and it is now described for the first time. Al- 

 though the structure of the feet in general, and especially 

 of the anterior pair, together with the presence of a spinous 

 scale on the outer side of the peduncle of the external 

 antennse, and some other characters, exhibit an aberration 



